Complete Blood Count (CBC)

Assist.Prof. Filiz BAKAR ATEŞ

Complete Blood Count

  The complete blood count (CBC) is one of the most

common blood test used.

  It analyzes the three major types of cells in blood 1.  red blood cells,

2.  white blood cells, and 3.  platelets.

  The CBC counts these cells, measures

  hemoglobin (the oxygen-carrying molecule in red

blood cells),

  estimates the red cells' volume, and

  sorts the white blood cells into five subtypes, referred

CBC TEST NAMES Acronym Definition

  WBC White Blood Cells   RBC Red Blood Cells   HGB Hemoglobin

  HCT Hematocrit

  MCV Mean Corpuscular Volume

  MCH Mean Corpuscular Hemoglobin

  MCHC Mean Corpuscular Hemoglobin Concentration   RDW Red Cell Distribution Width

  PLT Platelets

Which Specimen is Used ???

Cell Counts

  White cells, red cells (erythrocytes) and platelets are

counted per unit volume of whole blood.

  Unit volume: per cubic millimeter (mm3) which is the

Leucocytes

  White blood cells (WBC), sometimes referred to as leukocytes,

are produced by the immune system to help defend the body against infection.

  They are formed in the bone marrow and enter the blood for

migration to key organs; such as the spleen or lymph nodes.

  These cells are bigger than red blood cells, and there are far

fewer WBCs in the bloodstream.

  A high white blood cell count likely indicates that an infection

is present somewhere in the body,

  A low number might indicate that an infection or disease has

slowed the ability of the bone marrow to produce new white blood cells.

  Typically one cubic millimeter of blood contains about 10,000 white blood cells.

  There are several different types of white blood cells,

which are identified in a CBC with differential blood test.

Eritrocytes

  Red blood cells (RBC), often referred to as erythrocytes, are

responsible for delivering oxygen throughout the body.

  There are between 3.6 to 6.1 million in a single milliliter of

blood.

  A low red blood cell count can indicate anemia, which can lead

Hemoglobin

  Hemoglobin (HGB) is an iron-rich protein found inside red

blood cells which gives blood its red color.

  Oxygen travels through the bloodstream bound to hemoglobin.   The amount of hemoglobin in the blood is an indicator of the

amount of oxygen the blood can carry.

  A low hemoglobin number is a good indicator of anemia;

whereas, dehydration can temporarily increase hemoglobin levels

What does hematocrit represent?

  Hematocrit (HCT) refers to the amount of your blood that

is occupied by red blood cells.

  A low hematocrit percentage is a good indicators of

anemia.

  The value is expressed as a percentage of cells in blood.   For example, a hematocrit value of 42% means that there

are 42 milliliters of red blood cells in 100 milliliters of blood.

Mean Corpuscular Volume

  Mean Corpuscular Volume (MCV) measures the size of

red blood cells.

  Larger red blood cells may indicate anemia due to

vitamin B6 or folic acid deficiency; smaller red blood cells may indicate anemia due to iron deficiency.

  Some drugs can cause MCV to increase without

Mean Corpuscular Hemoglobin

  Mean corpuscular hemoglobin (MCH) measures the

amount of hemoglobin in red blood cells.

  Both hemoglobin and hematocrit are used to calculate

this number.

Red Cell Distribution Width

  Red blood cells can come in different sizes.

  Red cell distribution width (RDW) looks at the range

of these sizes in a blood sample.

  If anemia is suspected, based on other blood counts,

RDW test results are often used together with MCV results to figure out what the cause of the anemia might be.

Platelets

  Platelets (PLT) are tiny cells produced by the bone marrow to

help your blood clot in the event of a cut or scrape.

  A high number might be seen in people with cancer, a blood

disease, or rheumatoid arthritis.

  A decreased platelet count is called thrombocytopenia.

  There are a number of possible causes of thrombocytopenia,

including a disorder of the immune system that causes

antibodies produced by the spleen to kill platelets (idiopathic thrombocytopenia purpura).

  This can be problematic and often warrants immediate

Mean Platelet Volume

  The mean platelet volume (MPV) test measures the

average volume (size) of your platelets.

  A higher-than-normal MPV has been shown to be

associated with a greater risk of heart attacks and stroke.

CBC Differential

_…

What do the differential values represent?

white blood cells.

  There are actually two main types of white blood cells: 1.  Phagocytes

CBC Differential

_…

What do the differential values represent?

defenses against certain infections.

  Lymphocytes: which include T-cells, play a large role in

fighting chronic infections.

  The 5 subtypes of white blood cells are displayed both

as a percentage of white blood cells and as an absolute number of cells.

CBC DIFFERENTIAL TEST NAMES

  MONO Monocytes   EOS Eosinophils   BASO Basophils

Neutrophils (NEU)

  Surround, engulf, and destroy invading microbes.

  Normally accounting for anywhere between 38% and

80% of the white blood cell count.

  The bacterial infection; a low number can put you at

a greater risk of experiencing sickness from a bacterial infection.

Lymphocytes

  Produce antibodies, which are specific

proteins that attack and help destroy specific germs

  Lymphocytes include T-cells, B-cells, and

natural killer (NK) cells

  Account for between 15% and 49% of the

total white blood cell count.

  Viral infections can either increase or

decrease the total percentage of lymphocytes.

Monocytes (MONO) / Mononuclear phagocytes

  They remove dead cells and microbes from the blood.   A low number can put you at a higher risk of getting

sick from an infection, particularly those caused by bacteria.

Eosonophils (EOS)

  A type of phagocyte that produces the

anti-inflammatory protein histamine, are usually elevated in people with allergies or parasitic infections.

Basophil (BAS)

  Basophil (BAS) cells are responsible for controlling

inflammation and damage of tissues in the body, such as liver inflammation due to hepatitis.

References

  Clinical Biochemistry (Fundamentals of Biomedical

Science), Editor: Nessar Ahmed

  Handbook of Clinical Biochemistry, 2nd Edition, R.